Drivers on the Capital Beltway now have the option of using express lanes. / By H. Darr Beiser, USA TODAY

by Larry Copeland and Paul Overberg, USA TODAY

by Larry Copeland and Paul Overberg, USA TODAY

ATLANTA - Highway lanes that charge cars rising tolls as traffic increases are becoming the future for the USA's clogged urban expressways. A dozen now operate across the nation and another 18 are under development.

The so-called "dynamic pricing" lanes have just come to two of the biggest and most congested metro areas in the USA, Los Angeles and Washington, D.C. They join Atlanta, another notoriously congested city, and other metro areas where the roads - many called HOT (high-occupancy toll) lanes because carpoolers ride free - are growing in popularity after a rocky start.

They also are planned or under construction on congested urban corridors from Seattle to El Paso, Dallas, Baltimore and other cities.

Projects such as the ones in Los Angeles and Northern Virginia near Washington, which rolled out last month, likely represent the future of urban tolling in the USA because they allow transportation planners to get more mileage out of the existing highway system, experts say.

"I think they do represent the wave of the future in the 10-15 largest urban areas," says Bob Poole, director of transportation policy at the Reason Foundation, a libertarian policy research group.

Some opponents criticize them as "Lexus lanes" - serving the wealthy while leaving others stuck in traffic. Others oppose the lanes because they're on highways that motorists have already paid for with gas taxes and because the lanes are often turned over to private operators. "These public-private partnership deals generally are not in the best interest of motorists," says Steve Carrellas of the National Motorists Association.

These toll lanes offer commuters congestion relief by using technology to adjust pricing constantly. Tolls rise as more people use the lanes and drop as demand falls. Carpools, bus riders and motorcyclists use the lanes for free.

Most new toll projects in heavily traveled urban corridors around the USA employ real-time tolling, says Jim Ely, vice chairman of toll services for HNTB Corp., a national infrastructure firm.

A $105 billion, two-year highway authorization bill signed into law by President Obama in July gives states more flexibility on tolling. "We're going to see more (such) lanes on the interstates as a result of (the funding bill)," Ely says. "It allows them to add more price-managed lanes as long as they don't convert an existing general purpose lane (to tolls)."

The L.A. and Washington projects are gradually gaining popularity with drivers after an initial period of confusion and some resistance. Officials in both places expect more motorists to try the lanes as they become more familiar with them.